Multiple power board input (with charging port)

I'm trying to get an idea on price and timing on designing a prototype board. The complete module will include 3 parts, but this project is only about power management. All should be as power efficient as possible. Each input/output should be protect for reverse voltage/high voltage Able to sustain 70 degree Celsius -20 I'm open to any changes if it makes sens or add something. There is aboard with a RTC that will be waking up the power supply board by bus when needed. The idea is to get multiple and redundancy powers from different kind, they should work simultaneously We will have as power 4 input possible - Input A DC power 12V-40V input range (For external power supply AC to DC for example) - Input B DC power 12V-40V input range (For solar panel, for example) - Input/Charging C 12, 12.2V14.4V battery input/charging port. - Input/Charging D 12, 12.2V14.4V battery input/charging port. Battery type can be 3S 4S or Pb. Each input should have Intensity/Voltage monitoring by bus (I2C?) One micro-controller will ask each input about once every 30 mn or so to create record of variation. There is no Micro controller on this board, it just need to have a bus that a micro-controller can connect to. There are 2 extra inputs for temperature sensors that I can put on each battery to make sure they do not overheat, this reading will also be on the bus. Input C and D should also have temperature reading for the charger IC as well as Intensity/Voltage I will describe the outputs below, but here are possible modes the system could handle. - Only one battery plugged, either C or D The power drain the battery until limit reached (This level should be adjustable by bus as 3S or 4S battery have different value) -With 2 batteries connected only on C and D The power drain the battery until limit reached (This level should be adjustable by bus as 3S or 4S battery have different value) For now, I will assume each battery is the same kind, bu could be different capacity, so each charger should be independent. If plug a 50% charged battery and a 100%, I don't want the 100% battery charging the 50% one to balance. With only power input, no battery (either A or B or A and B, the system works also) If one power input (or 2) and one (or 2 batteries); the system is powered and extra energy is used to charge the batteries if needed) So, any possible combination of these should provide output power to the other boards. The outputs. The idea is to get very low voltage consumption as the system should be sleeping for long period of time with very little electricity to spare. So all voltage regulation as output should be also remotely addressable. If no output is requested, the system is not using any power. When the micro-controller wakes up, it ask the power board to deliver him +5V & + 3.3V and so start to use power from the input or/and battery only at this stage. The other outputs should be remotely controlled. - Output 1, Constant 3.3V to get the RTC working, I'm sure at this stage, but it need very little power. All the other outputs should be remotely controlled (turn on off when requested by bus) to not use power on power regulator when system sleep) - Output 2, Bus remote 5V for powering network board and main controller board. - Output 3, Programmable 7 to 9V output with reading on Intensity/Voltage, This output should be (turn on off when requested by bus), I will need to monitor closely at certain time the exact power consumption from this output to detect if the load was connected or not and drained the right amount. - Output 4, 5, 6 +12V 2A max (simple cooling fan / accessories / pump ) - Output 7, 8 +5V 2A max (USB accessories as hub/model/led ) - Optional 9 output with PMW 4 pin for speed fan control. [login to view URL] for a diagram Feel free to contact me if not clear. I hope to get this ins a very tiny 7 cm x 10 cm board